I don't know where you got the idea that the story in BG3 "miles deep." Miles wide perhaps, but not deep at all. They give the player lots and lots of choices, but without seeing characters reacting to events and interacting with each other, none of those hundreds of choices are particularly meaningful. The story in BG3 was the weakest link for me. I haven't played Solasta, so I can't compare that particular game, but NWN, NWN2, Pathfinder: Kingmaker, POE, POE2, and Tyranny were all stronger storywise than BG3 in my opinion.
Companions commenting on story events is something that is often missing in BG3, as it adds to characterization and helps to create that feeling of adventuring with a party. But it is not the same as the player shaping the story through their actions in the game. Something that was missing from NWN, for example. I don't remember if anything at all carried between the "modules" the original campaign was split to, but it was one of the weakest and forgettable stories I've experienced in games. Same with NWN2, and even having more party interactions (which it had compared to NWN) wasn't able to save it. Only the MotB did storytelling right, by focusing on how the player handled the spirit hunger.
It is at this point too early to tell with BG3, imo. There are some indications (and datamined spoilers) that some choices will lead to different outcomes in later chapters. And it seems like under certain circumstances some companions might impact the story as well (Gale and Raphael). Time will tell if it ends up more like NWN or MotB, though.
